Instead of having to close my panes and rearrange them, using Tmux I can create a new window, which is a collection of panes. I do that with control b c. C stands for create. My status bar changes to reflect the fact that I'm currently in window number one.
I had been in window zero which is currently active in the last program. Number one is currently using bash. The asterisk indicates that this is the current window. Now, I can get to work in this window. If I want I can also divide it into panes.
To switch back to the other window I use control b and then n. Control b n takes me to the next window. Control b p will take me to the previous window. You can see that I now I can flip between window zero and window one.
To make this a little bit clearer, we can open another window with control b c for create. Now we have windows zero, windows one, and windows two. I can cycle through them with control b n. It goes back to zero. Control b n, it goes back to one. A third time bring us back to right where we started.